JP4797938B2 - Carrier wave reproduction device, demodulator, reproduction carrier pseudo pull-in detection method, and program thereof - Google Patents

Description

  The present invention relates to a carrier recovery device, a demodulator, and the like suitable for use in a digital wireless communication system, and more particularly to a carrier recovery device, a demodulator, a method for detecting a pseudo carrier signal of a recovered carrier, and a program thereof.

As a demodulator used in a microwave digital radio communication system, for example, one having a basic configuration shown in FIG. 7 is known.
In the demodulator shown in FIG. 7, the synchronous / asynchronous detection of the reproduced carrier wave is performed by the C / N value calculated by the C / N (carrier wave / noise ratio) estimating circuit 90 and the C / N estimating circuit 90. This has been done by comparing the C / N threshold 161 set from the outside. That is, when the C / N value obtained by the calculation is lower than the C / N threshold, the operator determines that the reproduced carrier wave is asynchronous by the C / N alarm signal 162 generated and output by the C / N estimation circuit 90. It was.

On the other hand, many techniques for realizing synchronous pull-in of a reproduced carrier wave have been conventionally proposed. For example, a technique for preventing pseudo pull-in of a carrier wave using an APC (automatic phase control) signal that corresponds to a phase difference between a quadrature modulated wave and a reproduced carrier wave and is generated and output by a carrier wave reproducing circuit (see, for example, Patent Document 1) ), Or a technique for shortening the time taken from the re-intake of the regenerated carrier wave to the synchronization determination by using a reception signal area determination circuit instead of the C / N alarm signal 162 described above (for example, Patent Document 2, (See Patent Document 3).
JP-A-9-107384 JP 2003-229923 A JP 2006-157186 A

  However, according to the basic configuration of the carrier recovery circuit (conventional example) shown in FIG. 7 described above, when the recovered carrier causes a pseudo pull-in, the C / N estimation circuit 90 has all the pseudo pull-in due to the nature of the circuit. Therefore, it is necessary to detect pseudo pull-in using the frame asynchronous signal 163 generated by the frame synchronization circuit 63 connected to the subsequent stage.

  In FIG. 7, the time required to activate and cancel the frame asynchronous signal 163 requires extra time for synchronization in units of frames as compared to the activation and cancellation time of the C / N alarm signal 162. To do. For this reason, when the frame asynchronous signal 163 is used to detect the pseudo carrier pull-in of the regenerated carrier wave, it takes a long time until the received signal is restored to a normal state and the synchronization determination is performed after the redraw carrier is re-taken. .

  Further, as shown in the operation timing chart of FIG. 8, a sweep circuit (sweeper) 57 having a function of extending the regenerative carrier pull-in range has an APC auxiliary value having a control value (CARR APC control value) within the pull-in range. The signal 168 is generated and output. However, since the APC auxiliary signal 168 is free-running, there is a problem that the pseudo pull-in point of the reproduced carrier wave cannot be identified.

  For this reason, as shown in FIG. 9B, the operation timing is erroneously pulled at the same signal point position (pseudo pulling point) every time, which is a major factor in reducing the efficiency of redrawing the carrier wave. It was. This inconvenience is the same for the APC signal disclosed in Patent Document 1. Here, FIG. 9A shows an operation timing chart of the APC auxiliary signal when transitioning from the asynchronous state to the synchronous state when there is no pseudo pull-in point.

On the other hand, according to the techniques disclosed in Patent Document 2 and Patent Document 3 described above, the reception signal region determination circuit can detect the carrier pull-in at a high rate.
However, in this conventional example, since the recovery carrier pseudo pull-in is detected only at the signal point position of the received signal, as shown in FIG. 10 showing examples of pseudo pull-in in QPSK modulation, Although pseudo pull-in detection of ± fs / 8 deviation (FIG. 10 (a)) and ± fa / 12 deviation (FIG. 10 (b)) can be performed, ± n * fa as shown in FIG. 10 (c). / 4 (n = 1, 2,...) The pseudo pull-in of the deviation cannot be detected. Therefore, there is a disadvantage that it is impossible to detect all the pseudo pull-in of the reproduced carrier wave. In FIG. 10, symbol fs indicates a modulation speed.

(Object of invention)
The present invention improves the inconveniences of the above-described conventional example, and in particular, detects a pseudo carrier wave pull-in state by a demodulator alone without using a frame asynchronous signal generated by an externally connected frame synchronization circuit, and receives it. It is an object of the present invention to provide a carrier recovery device, a demodulator, a recovery carrier pseudo-intake detection method, and a pseudo-intake detection program that can significantly reduce the time from signal re-intake to synchronization determination.

  In order to achieve the above object, the carrier recovery apparatus according to the present invention generates a phase control signal by detecting the phase error between the orthogonally transformed digital signal and the reference signal, and reproduces the carrier signal based on the phase control signal. A reproduced carrier signal region determining unit that detects a position of a pseudo pull-in signal point of the reproduced carrier signal based on a signal point position in which the reproduced carrier signal is mapped in advance on a phase plane; and A phase control signal region determination control unit that generates a control signal for avoiding synchronous pull-in at the pseudo pull-in signal point position based on the phase control signal at the pseudo pull-in signal point position of the reproduced carrier signal. (Claim 1).

  Therefore, according to this, the reproduced carrier wave reception signal area determination unit detects the pseudo signal point position of the reproduced carrier signal based on the signal point position of the reproduced carrier signal in which the reproduced carrier signal is mapped on the phase plane. As a result, the rate at which the pseudo pull-in can be detected by the demodulator alone is increased without using the frame asynchronous signal generated by the frame synchronization circuit connected to the subsequent stage. Further, in this case, since the frame asynchronous signal is not required for detecting the pseudo pull-in state, the time from the re-drawing of the regenerated carrier signal to the synchronization determination can be greatly shortened.

  Further, by generating a control signal that avoids synchronous pull-in at the pseudo pull-in signal point position based on the phase control signal at the pseudo pull-in signal point position of the regenerated carrier signal, all the detection is performed only by the regenerated carrier wave reception signal region determination unit. It is possible to detect pseudo pull-in that could not be performed, and to prevent unnecessary synchronous pull-in at the same signal point position by the control signal generated by the phase control signal area determination control unit it can. For this reason, a carrier recovery circuit is provided that reduces the probability of occurrence of carrier pull-in and significantly reduces the time consumed for a series of operations from detection to re-entry and synchronization determination when pseudo pull-in occurs. I can do it.

  Here, the carrier wave recovery unit described above detects the phase error and generates a phase error signal having a value corresponding to the phase advance / delay of the recovered carrier signal, and the phase error detector A low-pass filter that removes high-frequency components from the output phase error signal and outputs the phase control signal; a numerically controlled oscillator that converts the phase control signal output by the low-pass filter into control angle information corresponding to the angle; A phase rotator that performs phase rotation control on the reproduced carrier wave signal based on control angle information output from the numerically controlled oscillator may be included.

  Further, the above-described reproduced carrier signal region determination unit is in the region where the above-described reproduced carrier signal is divided and allocated on the phase plane, and the signal point position of the reproduced carrier signal in the normal state is determined. When the ratios belonging to the first first area and the second area to which the reproduced carrier signal is mapped at the time of pseudo pull-in are calculated, and the ratio belonging to the second area is greater than or equal to a preset set value In addition, a configuration having a function of generating and outputting a pseudo pull-in state detection signal may be employed.

  Therefore, according to this, the reproduced carrier wave reception signal area determination unit detects the pseudo signal point position of the reproduced carrier signal based on the signal point position of the reproduced carrier signal in which the reproduced carrier signal is mapped on the phase plane. As a result, the rate at which the pseudo pull-in can be detected by the demodulator alone is increased without using the frame asynchronous signal generated by the frame synchronization circuit connected to the subsequent stage. In addition, since the frame asynchronous signal is not required for detecting the pseudo pull-in state, the time from re-pull-in to synchronization determination can be greatly shortened.

  In addition, the carrier recovery unit described above calculates a carrier / noise ratio based on the recovered carrier signal and compares the calculated carrier / noise ratio with a preset carrier / noise ratio. A noise ratio estimation circuit, and a synchronization detection circuit that detects the synchronization or asynchronization of the reproduced carrier signal described above based on the result of the comparison operation by the carrier wave / noise ratio estimation circuit and the determination result by the reproduced carrier signal region determination unit A configuration may also be adopted (claim 4).

  Further, the above-described phase control signal region determination control unit is in the pseudo pull-in state, and the synchronization detection unit detects synchronization of the reproduced carrier signal and is externally connected in advance to detect synchronization / asynchrony in the frame period. When the frame synchronization detection circuit that detects non-synchronization detects a phase control signal region determination circuit that determines the control value of the phase control signal as the pseudo pull-in signal point position, and based on a determination result by the phase signal region determination circuit A sweep circuit that generates a control signal that avoids synchronous pull-in at the pseudo pull-in signal point position may be provided.

Therefore, according to this, the reproduction carrier phase signal area determination circuit controls the control value of the control signal when the synchronization detection circuit detects the synchronization of the reproduction carrier signal and the externally connected frame synchronization detection circuit detects the frame asynchrony. Is determined as a pseudo acquisition signal point position, and the sweep circuit that has received this generates a control signal that avoids synchronous acquisition at the pseudo acquisition signal point position. Then, it is possible to detect the pseudo pull-in of the carrier wave that could not be detected at all, and to prevent unnecessary synchronous pull-in at the signal point position by the control signal.
As a result, the probability of occurrence of carrier pull-in can be reduced, and the time spent for a series of operations from detection to re-draw and synchronization determination when pseudo pull-in can occur can be significantly reduced.

  In addition, when the reproduced carrier signal transitions from the asynchronous state to the synchronous state, the sweep circuit described above retains the control value immediately before the transition of the control signal and the control signal based on the retained control value. It is good also as a structure provided with the function to produce | generate and output to the said carrier wave reproduction | regeneration part (Claim 6).

  Therefore, according to this, when the reproduced carrier signal transitions from the asynchronous state to the synchronous state, the sweep circuit can be provided with a learning function by holding the control value immediately before the control signal, and the pseudo carrier wave pull-in It is possible to avoid unnecessary synchronization pull-in of signal point positions that frequently occur.

  Furthermore, an intermittent reset signal generation circuit that prohibits generation of a reproduced carrier signal by the carrier recovery unit when the above-described synchronization detection circuit detects an asynchronous state may be provided in the carrier recovery unit. ).

  In order to achieve the above object, in the demodulator according to the present invention, the carrier wave recovery device described above and the received modulated wave signals provided in the input stage of the carrier wave recovery device are orthogonal to each other based on the reference frequency signal. An orthogonal detector for converting into a signal and an analog-to-digital converter for converting the baseband signal into a digital signal are provided (claim 8).

  For this reason, according to this, the carrier recovery device constituting the main part of the demodulator performs the pseudo acquisition signal point position of the recovered carrier signal based on the signal point position of the recovered carrier signal in which the recovered carrier signal is mapped on the phase plane. By detecting this, the demodulator alone can detect the pseudo pull-in state of the carrier wave. At this time, since the frame asynchronous signal is not required for detecting the pseudo-intake state of the carrier wave, the time from the re-intake to the synchronization determination can be greatly shortened.

  Further, the carrier recovery device constituting this demodulator generates a control signal that avoids synchronous pull-in at the pseudo pull-in signal point position based on the phase control signal at the pseudo pull-in signal point position of the carrier, thereby Unnecessary synchronization pull-in can be prevented in advance, so the probability of occurrence of carrier pull-in is reduced, and when pseudo pull-in occurs, a series of operations from detection to re-drawing, synchronization determination, It is possible to provide a demodulator that significantly reduces the time consumed.

  In order to achieve the above object, a method for detecting a pseudo-carrier wave according to the present invention is a method for detecting a pseudo-carrier wave in a demodulator that demodulates an incoming received modulated wave signal. A first step of converting the converted baseband signal into a digital signal, and detecting a phase error between the orthogonally-converted digital signal and a preset reference signal to control the phase A second step of generating a signal and generating a regenerated carrier signal based on the phase control signal; and a signal point position where the generated regenerated carrier signal is mapped on a phase plane. A third step of detecting a pseudo pull-in signal point position; and a position of the reproduced carrier signal at the pseudo pull-in signal point position. Based on the control signal and having a fourth step of generating a control signal which avoids synchronization pull in the pseudo pull-in signal point position (claim 9).

  Therefore, according to this, the carrier recovery device constituting the demodulator detects the pseudo signal point position of the recovered carrier signal based on the signal point position of the recovered carrier signal in which the recovered carrier signal is mapped on the phase plane. By executing the third step, it is possible to detect the pseudo pull-in state by the demodulator alone. At this time, since the frame asynchronous signal is not required for detection of the pseudo pull-in state, the time from re-pull-in to synchronization determination can be greatly shortened.

  In addition, the carrier recovery device constituting the demodulator executes a fourth step of generating a control signal for avoiding synchronous acquisition at the pseudo acquisition signal point position based on the phase control signal at the pseudo acquisition signal point position of the reproduction carrier signal. By doing so, unnecessary synchronization pull-in at the same signal point position can be prevented in advance, and therefore, the probability of occurrence of pseudo-pull-in of the carrier wave is reduced, and when pull-in occurs, re-pull-in from the detection, The time consumed for a series of operations up to the synchronization determination can be greatly reduced.

  Here, in the above-described fourth step, the control value immediately before the phase control signal is held when the reproduced carrier signal transitions from the asynchronous state to the synchronous state, and the control is performed based on the held control value. You may comprise so that the substep which produces | generates a signal may be included (Claim 10).

  Therefore, according to this, when the regenerative carrier signal transitions from the asynchronous state to the synchronous state, the learning function can be provided by holding the control value immediately before the control signal, and the pseudo pull-in of the carrier frequently occurs. Thus, it is possible to effectively avoid the synchronization pull-in at the signal point position.

In order to achieve the above object, a pseudo acquisition detection program according to the present invention is a program for detecting a pseudo acquisition state of a carrier wave in a demodulator that demodulates an incoming reception modulation wave signal, the reception modulation wave Signal conversion processing function that converts signals into orthogonal baseband signals and converts the converted baseband signals into digital signals, detects phase errors between the orthogonally converted digital signals and reference signals, and controls the phase A regenerated carrier signal generating function for generating a signal and generating a regenerated carrier signal based on the phase control signal; and a signal point position where the generated regenerated carrier signal is mapped on a phase plane. A pseudo pull-in signal point position detection processing function for detecting a pseudo pull-in signal point position, and the reproduction carrying Causing a computer to execute a control signal generation processing function for generating a control signal for avoiding synchronous pull-in at the pseudo pull-in signal point position based on the phase control signal at the pseudo pull-in signal point position of the wave signal and outputting the control signal to the carrier recovery unit This is characterized in that (claim 11).
Even in this case, it is possible to obtain substantially the same effect as in the case of the above-described method for detecting the pull-in of a carrier wave.

  In the control signal generation processing function described above, the control value immediately before the phase control signal is held and the held control value is set when the reproduced carrier signal transitions from the asynchronous state to the synchronous state. It may be configured to include a sub-processing function for generating the control signal based on this, and to cause the computer to execute the function.

  Since the present invention is configured and functions as described above, according to this, without using a frame asynchronous signal generated by an externally connected frame synchronization circuit, a demodulator alone detects a pseudo carrier pull-in state, It is possible to provide an unprecedented superior carrier recovery device, demodulator, carrier pseudo-pull-in detection method, and program thereof that can significantly reduce the time from re-reception of a received signal to synchronization determination. .

(Configuration explanation)
FIG. 1 is a block diagram showing a configuration of a demodulator according to an embodiment of the present invention. In the embodiments of the present invention described below, the modulation scheme is a quadrature modulation scheme such as QPSK (Quadrature Phase Shift Keying) or QAM (Quadrature Amplitude Modulation), and the detection scheme is a demodulator assuming a quasi-synchronous detection scheme. The notation of I component (real part: Ich) and Q component (imaginary part: Qch), which are general as the notation of the orthogonal baseband components, shall be used.

  As shown in FIG. 1, the demodulator according to the embodiment of the present invention includes a quadrature detector 1, an oscillator 2, an analog / digital converter (A / D converter) 3, and a carrier recovery device 4. It is configured. Further, for example, a microwave digital communication system using this demodulator as a component further includes a frame synchronization circuit 5. The frame asynchronous signal 123 generated by the frame synchronization circuit 5 is supplied to a reproduction carrier APC signal area determination circuit 64 that constitutes the carrier reproduction device 4. Details of the carrier wave reproducing device 4 and the reproduced carrier wave APC signal area determination circuit 64 will be described later.

In FIG. 1, a quadrature detector 1 and a transmitter 2 convert a received modulated wave signal, that is, an intermediate frequency signal (IFIN) 101 input to a demodulator into baseband signals Ich103 and Qch104. , Output to the A / D converter 3.
The oscillator 2 described above in the demodulator outputs a reference frequency signal for generating a regenerated carrier wave, and is free-running at a frequency close to that of an oscillator that outputs a carrier wave in a modulator on the transmitter side (not shown). ing.
The A / D converter 3 converts the analog baseband signal Ich103 into a digital baseband signal Ich105 and the analog baseband signal Qch104 into a digital baseband signal Qch106 in order to digitize the subsequent processing. Then, the data is output to the carrier reproducing unit 40 constituting the carrier reproducing device 4.

  The carrier wave reproducing device 4 described above detects a phase error between the orthogonally transformed digital signal and the reference signal to generate a phase control signal, and generates a reproduced carrier signal based on the phase control signal. A reproduced carrier signal region determination unit 50 for detecting the position of the pseudo carrier signal point of the reproduced carrier signal based on a signal point position in which the reproduced carrier signal is mapped in advance on a phase plane; and pseudo reproduction of the reproduced carrier signal And a phase control signal region determination control unit 60 for generating a control signal for avoiding synchronous pull-in at the pseudo pull-in signal point position based on a phase control signal at the signal point position.

  Therefore, according to this, the reproduced carrier wave reception signal area determination unit 50 detects the pseudo signal point position of the reproduced carrier signal based on the signal point position of the reproduced carrier signal in which the reproduced carrier signal is mapped on the phase plane. As a result, the rate at which pseudo-pulling-in can be detected by the demodulator alone is increased without using the frame asynchronous signal generated by the frame synchronization circuit 5 connected in the subsequent stage. Further, in this case, since the frame asynchronous signal is not required for detecting the pseudo pull-in state, the time from the re-drawing of the regenerated carrier signal to the synchronization determination can be greatly shortened.

  Further, by generating a control signal that avoids synchronous pull-in at the pseudo pull-in signal point position based on the phase control signal at the pseudo pull-in signal point position of the regenerated carrier signal, all the detection is performed by the regenerated carrier signal region determination unit 50 alone. It is possible to detect pseudo pull-in that could not be performed, and to prevent unnecessary synchronous pull-in at the same signal point position by the control signal generated by the phase control signal region determination control unit 60 Can do. For this reason, the carrier regeneration device 4 that reduces the probability of occurrence of pseudo pull-in of a carrier wave and greatly reduces the time consumed for a series of operations from detection to re-pull-in and synchronization determination when pseudo pull-in occurs. Can be provided.

  Here, the carrier recovery unit 40 described above detects the phase error and generates a phase error signal having a value corresponding to the phase advance / delay of the recovered carrier signal, and this phase error detection. A low-pass filter 46 that outputs the phase control signal by removing high-frequency components from the phase error signal output by the detector 45, and converts the phase control signal output by the low-pass filter 46 into control angle information corresponding to the angle. A numerical control oscillator 59 and a phase rotator 4 that performs phase rotation control on the reproduced carrier wave signal based on control angle information output from the numerical control oscillator 59 are included.

  Further, the above-described reproduced carrier signal region determination unit 50 will be described in detail later, but this is within the region where the above-described reproduced carrier signal is divided and allocated on the phase plane, and when it is normal. The ratio belonging to each of the first area centered on the signal point position of the reproduced carrier signal and the second area to which the reproduced carrier signal is mapped at the time of pseudo pull-in is calculated, and the ratio belonging to the second area Is configured to have a function of generating and outputting a pseudo pull-in state detection signal when is equal to or greater than a preset set value.

  Therefore, according to this, the reproduced carrier wave reception signal area determination unit 50 detects the pseudo signal point position of the reproduced carrier signal based on the signal point position of the reproduced carrier signal in which the reproduced carrier signal is mapped on the phase plane. As a result, the rate at which pseudo-pulling-in can be detected by the demodulator alone is increased without using the frame asynchronous signal generated by the frame synchronization circuit 5 connected in the subsequent stage. In addition, since the frame asynchronous signal is not required for detecting the pseudo pull-in state, the time from re-pull-in to synchronization determination can be greatly shortened.

This will be described in detail below.
In the carrier wave reproducing device 4 described above, in addition to the carrier wave reproducing unit 40, a reproduced carrier signal region determining unit (reproduced carrier signal region determining circuit 50) added according to the present embodiment, and a phase control signal region determining control unit 60 (reproducing) The carrier APC signal area determination circuit 64, the sweep circuit 67), a C / N estimation circuit 70, a synchronization detection circuit 80, and a reset signal generation circuit 90.

The carrier recovery unit 40 has a function of generating a phase control signal by detecting a phase error between the orthogonally transformed digital signal and the reference signal, and generating a playback carrier signal based on the phase control signal. A phase error detector 45, a low-pass filter (LPF 46), an adder circuit 48, and a numerically controlled oscillator 49.
The phase rotator 44 performs phase rotation control by digital signal processing on the phase rotation remaining in the digital signals Ich 105 and Qch 106, and outputs reproduced carrier wave signals Ich 107 and Qch 108.

  The phase error detector 45 detects a phase error from the reproduced carrier signals Ich107 and Qch108 output from the phase rotator 44, and has a phase error having a value corresponding to the phase advance / delay of the reproduced carrier signal (CARR). A signal 116 is generated and output to the LPF 46. The phase error detector 45 only needs to know whether the phase of the reproduced carrier signal is advanced or delayed. For example, +1 may be output if the phase is advanced, -1 may be output if the phase is delayed, or a continuous value may be output according to the magnitude of the phase delay advance.

  Further, the LPF 46 eliminates high frequency components from the phase error signal 116 output from the phase error detector 45 to generate a phase control signal (here, the phase error integrated signal 117) and supplies it to one input terminal of the adder circuit 48. Output. The other input terminal of the adder circuit 48 is supplied with a CARR APC auxiliary signal 118 generated and output by a sweep circuit 67 of a phase control signal region determination control unit 60 described later.

  In the adder circuit 48 described above, the signals (phase error integration signal 117 and CARR APC auxiliary signal 118) supplied to both input terminals are combined to generate a CARR APC signal 119 as a phase control signal, which is numerically controlled. It is output to the oscillator 49. The numerically controlled oscillator 49 converts the CARR APC signal 119 output via the adder circuit 48 into control angle information (Cos 120 and Sin 121) consisting of a cosine value or a sine value according to the angle, respectively, and the phase rotator 44. Output to.

The phase rotator 44 performs phase rotation control on the reproduction carrier signal described above based on the control angle information output from the numerically controlled oscillator 49, and as the reproduction carrier signals IchOUT107 and QchOUT108, for example, microwave digital radio The data is output to a circuit block in the subsequent stage constituting the communication system.
As described above, the oscillator 2 is free-running at a frequency close to the oscillator of the modulator on the transmission side (not shown). Therefore, the phase rotation of the difference frequency between the modulator and the demodulator oscillator remains. The phase rotator 44 converges the signal by applying a reverse rotation to the phase rotation by digital signal processing.

On the other hand, the reproduced carrier signal region determination circuit 50 receives the reproduced carrier signals Ich 107 and Qch 108 that are the outputs of the phase rotator 44 as inputs, generates a pseudo pull-in region detection signal 113 according to the procedure described later, and outputs it to the synchronization detection circuit 80. Therefore, based on the signal point position where the reproduced carrier signal is mapped on the phase plane (described later), it operates as a reproduced carrier signal region determining unit for detecting the pseudo signal point position of the reproduced carrier signal.
Details of the reproduced carrier signal region determination circuit 50 will be described later with reference to a phase plan view (FIG. 4) on which the reproduced carrier signal is mapped.

  Further, the phase control signal area determination control unit 60 has a function of generating a control signal for avoiding synchronous pull-in at the pseudo pull-in signal point position based on the phase control signal at the pseudo pull-in signal point position of the reproduced carrier signal, and an APC signal The region determination circuit 64 and the sweep circuit 67 are configured.

Among these, the APC signal region determination circuit 64 detects synchronization of the reproduced carrier signal, and detects synchronization and asynchrony in the frame period when the synchronization detection circuit 90 described later detects the synchronization of the reproduced carrier signal in a pseudo carrier pull-in state. When the frame synchronization detection circuit 5 detects asynchrony, the control value of the CARR APC auxiliary signal 118 is determined as the pseudo pull-in signal point position, and the pseudo pull-in CARR APC signal 122 is output to the sweep circuit 67.
The sweep circuit 67 generates a control signal (CARR APC auxiliary signal) that avoids the synchronous pull-in at the pseudo pull-in signal point position based on the pseudo pull-in CARR APC signal 122 output from the APC signal area determination circuit 64, and adds the circuit. Output to the numerically controlled oscillator 49 via 48.

  The sweep circuit 67 described above generates the CARR APC auxiliary signal 118 in order to expand the pull-in range of the recovered carrier when the recovered carrier is asynchronous, and realizes a learning function described later when the recovered carrier is synchronized. To keep the previous value. Further, as described above, the sweep circuit 67 operates so as to avoid the signal point position where the reproduced carrier wave has caused the pseudo pull-in by using the pseudo pull-in CARR APC signal 122 generated by the APC signal region determination circuit 64. A CARR APC auxiliary signal 118 is generated.

On the other hand, the C / N estimation circuit 70 calculates an estimated C / N value using the regenerated carrier wave signals Ich 107 and Qch 108, compares it with a preset C / N threshold value 111, and compares it with the C / N threshold value 111. When the estimated C / N value is low, it is determined that the reproduced carrier signal is in an asynchronous state, and the C / N alarm signal 112 is output to the synchronization detection circuit 80.
The synchronization detection circuit 80 performs an OR operation between the C / N alarm signal 112 generated by the C / N estimation circuit 80 and the pseudo acquisition area detection signal 113 generated and output by the reproduction carrier signal area determination circuit 50. The asynchronous detection signal 114 is output to the intermittent reset signal generation circuit 90.

Further, the intermittent reset signal generation circuit 90 generates a reset pulse at a constant cycle, and when receiving the asynchronous detection signal 114 from the synchronization detection circuit 80, the intermittent reset signal generation circuit 90 and the phase control signal region determination control unit 60 An intermittent reset signal 115 is output to both of the sweep circuits 67.
The frame synchronization circuit 5 is an external circuit for determining whether the frame period is synchronous or asynchronous. When the frame is asynchronous, a frame asynchronous signal 123 is generated and the APC signal area determination of the phase control signal area determination control unit 60 is performed. The signal is output to the circuit 64 and the synchronization detection circuit 80.

(Description of operation)
FIG. 2 is a flowchart for explaining the basic operation of the demodulator in this embodiment. FIG. 3 is a flowchart showing in detail the reproduction carrier signal region determination operation by the reproduction carrier signal region determination circuit 50, and FIG. 5 is a flowchart showing in detail the operation of phase control signal region determination control by the APC signal region determination circuit 64 and the sweep circuit 67. It is.
The operation of the demodulator in this embodiment shown in FIG. 1 will be described below with reference to the flowcharts of FIGS.

  First, the input signal IFIN101 is converted into baseband signals Ich103 and Qch104, which are two signal components orthogonal to each other, by the oscillator 2 and the quadrature detector 1 (step S201 in FIG. 2). Subsequently, the Ich signal component 103 and the Qch signal component 104 are converted into baseband signals Ich 105 and Qch 106 digitized by the A / D converter 3 and output to the phase rotator 44 of the carrier wave reproducing unit 40 ( Step S202).

  By the way, the synchronization of the recovered carrier signal is established by the phase rotator 44, the phase error detector 45, the LPF 46, the sweep circuit 47, the adder circuit 48, the numerically controlled oscillator 49, and the phase control signal region. The sweep circuit 67 of the determination unit 60 performs synchronization and asynchronous detection of the reproduced carrier signal. The reproduced carrier signal region determination circuit 50, the CARR APC signal region determination circuit 64, the C / N estimation circuit 70, and the synchronization detection This is done in circuit 80. Hereinafter, the operation will be described by paying attention to the carrier wave reproducing device 4.

First, the C / N estimation circuit 70 calculates an estimated C / N value of the signal using the reproduced carrier signals Ich 107 and Qch 108 output from the phase rotator 44 (step S203), and sets a preset C / N threshold value. 111 is compared (step S204). Here, when it is determined that the estimated C / N value is lower than the C / N threshold value 111, the C / N estimation circuit 70 determines that the reproduced carrier signal is in an asynchronous state, and sends a C signal to the synchronization detection circuit 80. The / N alarm signal 112 is output (step S205).
The estimated C / N value in the C / N estimation circuit 70 is calculated by, for example, obtaining the variance of each of the Ich 107 and Qch 108, adding them, and obtaining the noise power to obtain the estimated C / N value. This is done by calculating.

  Subsequently, the synchronization detection circuit 80 performs an OR operation between the C / N alarm signal 112 generated by the C / N estimation circuit 70 and the pseudo acquisition area detection signal 113 generated by the reproduction carrier signal area determination circuit 50. The asynchronous detection signal 114 is generated and output to the intermittent reset signal generation circuit 90 (step S206). Details of generation of the pseudo entrainment region detection signal 113 by the reproduction carrier signal region determination circuit 50 will be described later.

  The intermittent reset signal generation circuit 90 generates the intermittent reset signal 115 for the LPF 46 and the sweep circuit 67 of the phase control signal region determination unit 60 when the asynchronous detection signal 114 generated and output by the synchronization detection circuit 80 is received. A reset signal that outputs and inhibits generation of the carrier wave reproduction signal is generated (step S207).

By the way, in the conventional carrier recovery apparatus, the detection of the synchronization / asynchronization of the carrier is performed using the C / N estimation circuit 70. However, depending on the value of the C / N threshold value 111 set by the C / N estimation circuit 70, there is a possibility that the synchronization characteristic of the reproduced carrier wave changes.
For example, suppose that the C / N threshold 111 is set to a value close to the estimated C / N value in the synchronized state of the reproduced carrier wave. At this time, if noise is added and the estimated C / N value decreases, the C / N estimation circuit 70 determines that the regenerated carrier wave is in an asynchronous state even though the regenerated carrier wave is in a synchronous state. The C / N alarm signal 112 is generated and output. Therefore, the LPF 46 is reset and becomes unstable.

  On the other hand, when the C / N threshold value 111 is set low, the C / N estimation circuit 70 determines that the C / N estimation signal 70 is in a synchronized state even in the pseudo pull-in state. At this time, the C / N alarm signal 112 is not output. It is difficult to detect the pseudo pull-in alone, and it is necessary to detect the pseudo pull-in using a frame asynchronous signal by the frame synchronization circuit 5 at the subsequent stage.

  In general, the frame asynchronous signal activation and release time is longer than the C / N alarm signal 112 activation and cancellation time, and it takes more time to synchronize in units of frames. When a frame asynchronous signal is used for this, it takes a lot of time until the received signal is restored to a normal state and then a synchronization determination is made. For this reason, in the present embodiment, a reproduced carrier signal region determination circuit 50 as a reproduced carrier signal region determination unit is added in order to facilitate the detection of the pseudo carrier wave by the demodulator alone. Next, this will be described.

For example, in the QPSK, the reproduced carrier signal region determination circuit 50 has an A region (centered on the signal point position of the reproduced carrier signal in the normal state as shown in FIG. 4 as an example divided into regions using a phase plan view. The first area) is divided into a B area (second area) where a signal point of the reproduced carrier signal is supposed to exist at the time of pseudo pull-in, and the reproduced carrier signal is mapped (assigned) to each area. Thus, the presence / absence of a pseudo carrier wave pull-in state is detected (step S301 in FIG. 3).
That is, the reproduced carrier signal region determination circuit 50 calculates the proportion of the reproduced carrier belonging to the A region and the B region at a predetermined time (step S302), and if the proportion belonging to the B region is equal to or greater than a certain value (threshold). (Step S303: =), it is determined that the reproduced carrier wave signal is in a pseudo-attraction state, and a pseudo attraction area detection signal 113 is output (Step S304).

  By using the pseudo pull-in area detection signal 113 described above, it is possible to detect pseudo pull-in without using a frame asynchronous signal generated and output by the frame synchronization circuit 5 connected externally. Therefore, the time required for a series of operations from the re-acquisition of a carrier wave after detection of pseudo acquisition to the synchronization determination can be greatly shortened.

As described above, by adding the reproduced carrier signal region determination circuit 50, it is possible to detect the pseudo pull-in of the reproduced carrier at a relatively high rate. However, since the reproduced carrier signal region determination circuit 50 detects the pseudo carrier pull-in of the reproduced carrier signal only at the signal point position of the reproduced carrier signal, FIG. 10 shows an example of the pseudo carrier in QPSK modulation due to the nature of the circuit. As shown in FIG. 10 (c), pseudo-lead detection of ± fs / 8 deviation (FIG. 10 (a)) and ± fa / 12 deviation (FIG. 10 (b)) of the reproduced carriers Ich and Qch can be performed. Therefore, it is not possible to detect the pseudo pull-in of the “± n * fa / 4 (n = 1, 2,...)” Shown in FIG. It is not possible to detect all the pseudo pull-ins.
For this reason, in the present embodiment, a phase control signal region determination control unit 60 (APC signal region determination circuit 64) is further added to identify a pseudo lead-in signal point position that cannot be detected by the reproduction carrier signal region determination circuit 50. It was. This will be described in detail below.

  By the way, as described above, the oscillator 2 is free-running at a frequency close to the oscillator on the modulator side (not shown), and the phase rotation of the frequency difference between the oscillator and the demodulator (not shown) remains. Yes. The numerically controlled oscillator 49 is generated by a control value (phase error integration signal 117) corresponding to the above difference generated by the phase error detector 45 and the LPF 46 and a sweep circuit 67 used to widen the carrier pull-in range. A CARR APC signal 119 obtained by adding the CARR APC auxiliary signal 118 to be added by the adder circuit 48 is supplied.

  Therefore, the APC signal area determination circuit 64 acquires the CARR APC signal 119 from the adder circuit 48 (step S501 in FIG. 5), and thereby detects a pseudo pull-in state (step S502: YES). Since the control values of the phase error integration signal 117 and the CARR APC auxiliary signal 118 are stable even in the pseudo pull-in state, the APC signal region determination circuit 64 indicates that the asynchronous detection signal 114 output from the synchronization detection circuit 80 is in a synchronized state. (Step S503: YES), the control value of the CARR APC auxiliary signal 118 when the frame asynchronous signal 123 output by the frame synchronization circuit 5 indicates the asynchronous state (step S504: YES) (Step S505), and the signal point position is output to the sweep circuit 67 as a pseudo pull-in APC signal 122.

  As a result, the sweep circuit 67, as shown in FIG. 6 (b), shows a CARR APC that avoids synchronous pull-in at the signal point position (pseudo pull-in point) of the pseudo pull-in CARR APC signal 122. The auxiliary signal 118 can be generated. The sweep circuit 67 can prevent false carrier wave pull-in by generating the CARR APC auxiliary signal 118 having a control value corresponding to the hatched portion of FIG. 6B (step S506). .

  Further, the sweep circuit 67 can have a learning function by holding the control value immediately before the CARR APC auxiliary signal 108 when the reproduced carrier signal transitions from the asynchronous state to the synchronous state. In other words, it is possible to avoid the synchronous pull-in of the signal point position occurring in the above. FIG. 6A shows an operation timing chart of the CARR APC auxiliary signal 108 when transitioning from the asynchronous state to the synchronous state when there is a pseudo pull-in point. Moreover, in FIG. 6A, it is shown that between AB and CD is a pseudo pull-in point.

  As described above, the reproduction carrier signal region determination unit (reproduction carrier signal region determination circuit 50) and the phase control signal region determination control unit 60 (CARR APC signal region determination circuit 64) perform pseudo pull-in of the reproduction carrier by the demodulator alone. In addition, the overall digital wireless communication system using this demodulator reduces the probability of occurrence of pseudo pull-in of a regenerated carrier wave, and when pseudo pull-in occurs, The time can be shortened for a series of operations up to the synchronization determination.

  At this time, the phase control signal region determination control unit 60 (sweep circuit 67) learns by holding the control value immediately before the CARR APC auxiliary signal 108 when the reproduced carrier signal transitions from the asynchronous state to the synchronous state. By providing a function, it is possible to avoid the synchronous pull-in of signal point positions where the pseudo pull-in of the carrier frequently occurs, and the time can be further reduced.

  The carrier recovery device 4 described above constitutes a main part of a demodulator used in a digital radio communication system. In this case, as described above, the demodulator, based on the reference frequency signal (output from the oscillator 2), converts the received modulation wave signal into baseband signals orthogonal to each other, and the baseband signal into a digital signal. An A / D converter 3 for conversion and a carrier recovery device 4 are included.

  Here, the carrier recovery device 4 detects a phase error between the digital signal and the reference signal, generates a phase control signal, generates a recovered carrier signal based on the phase control signal, and the recovered carrier signal is in phase. A reproduced carrier signal region determining unit (reproduced carrier signal region determining circuit 50) that detects a pseudo signal point position of the reproduced carrier signal based on a signal point position mapped on a plane; A carrier wave / noise ratio estimation circuit 70 for calculating a noise ratio and comparing the calculated carrier wave / noise ratio with a predetermined carrier wave / noise ratio, a comparison operation result by the carrier wave / noise ratio estimation circuit 70 and the reproduction A synchronization detection circuit 80 for detecting the synchronization or asynchronization of the reproduced carrier signal based on the determination result by the carrier signal region determining circuit 50; A phase control signal region determination control unit 60 (APC signal region determination circuit 64, sweep circuit 67) that generates a control signal for avoiding synchronous pull-in at the pseudo pull-in signal point position based on the phase control signal at the pseudo pull-in signal point position; The synchronous detection circuit 80 includes an intermittent reset signal generation circuit 90 that prohibits the generation of a reproduced carrier signal by the carrier reproduction unit 40 when an asynchronous state is detected.

The demodulator described above is used, for example, in a microwave digital radio communication system. In the demodulator, a reproduction carrier signal region determination circuit 50 is added to the carrier wave reproduction device 4, thereby using the signal point position of the received signal. Detection of pseudo pull-in is possible, and the ratio of pseudo pull-in detection by the demodulator alone can be increased.
Further, by adding the phase control signal region determination unit 60 (APC signal region determination circuit 60 and sweep circuit 67), the pseudo pull-in APC signal 122 at the time of pseudo pull-in is identified, and the sweep circuit 67 detects the pseudo pull-in signal point. By generating a control signal (CARR APC auxiliary signal 118) that avoids the synchronous pull-in at the position, it becomes possible to prevent the false pull-in of the carrier.

  Accordingly, in a general digital radio communication system including a microwave digital radio communication system, the probability of occurrence of pseudo pull-in of a carrier wave is lowered, and when pseudo pull-in occurs, a series of operations from detection to re-pull-in and synchronization determination The time can be shortened.

  The flowcharts shown in FIGS. 2, 3, and 5 show not only the operation of the demodulator shown in FIG. 1, but also the steps of the method for detecting the pseudo carrier wave in the demodulator according to the present embodiment. It is a thing.

  That is, in the operation of the demodulator in the present embodiment, at least the received modulated wave signal is converted into mutually orthogonal baseband signals in the sequence control for detecting the pseudo pull-in of the carrier wave, and the baseband signal is converted into the baseband signal. A first step of converting to a digital signal (steps S201 and S202 in FIG. 2), a phase error between the digital signal subjected to orthogonal transformation and the reference signal is detected to generate a phase control signal, and based on the phase control signal A second step of generating a reproduced carrier signal (step S202), and a third step of detecting a pseudo lead-in signal point position of the reproduced carrier signal based on the signal point position where the reproduced carrier signal is mapped on the phase plane (Steps S301 to S304 in FIG. 3), the position of the reproduced carrier signal at the position of the pseudo lead-in signal point Based on the control signal, (step S501~S506 of FIG. 5) a fourth step and generating a control signal which avoids synchronization pull in the pseudo pull-in signal point position, it is adapted to successively execute a.

In the fourth step, when the reproduced carrier signal transitions from the asynchronous state to the synchronous state, the control value immediately before the control signal is retained, and thereafter, the control signal is generated based on the retained control value. Steps may be included.
Also, the estimated C / N value is calculated from the regenerated carrier wave (step S203 in FIG. 2), and the synchronization and asynchrony of the regenerated carrier signal are monitored by comparison with a preset C / N threshold value 111 (FIG. 2). Steps S203 to S205), if it is determined that the state is asynchronous, the fifth step for performing the OR operation with the determination result in the third step described above and prohibiting the generation of the carrier recovery signal is executed (Step S203 to S205). Steps S206 and S207).

  In addition, according to the method for detecting a pseudo carrier wave in the demodulator according to the above-described embodiment, the carrier recovery device 4 constituting the demodulator has a signal point of the recovered carrier signal in which the recovered carrier signal is mapped on the phase plane. By executing the third step of detecting the pseudo acquisition signal point position of the regenerated carrier signal based on the position, the demodulator alone can detect the pseudo acquisition state. At this time, since a frame asynchronous signal is not required for detection of a pseudo pull-in state, it is possible to provide a method for detecting a pull-in of a carrier wave in a demodulator that greatly shortens the time from re-pull-in of a received signal to synchronization determination.

  Further, the carrier wave recovery device 4 constituting the main part of the demodulator generates a control signal for avoiding synchronous pull-in at the pseudo pull-in signal point position based on the phase control signal at the pseudo pull-in signal point position of the reproduced carrier signal. By executing this step, it is possible to prevent unnecessary synchronization pull-in at the same signal point position.For this reason, the probability of occurrence of carrier pull-in is reduced, and at the time of pseudo pull-in, the detection is performed. Thus, it is possible to provide a method for detecting a pseudo carrier wave in a demodulator in which a time consumed for a series of operations from redrawing of a received signal to synchronization determination is greatly reduced. Also, when the recovered carrier signal transitions from the asynchronous state to the synchronous state, a learning function can be provided by holding the control value immediately before the control signal, and the signal point position where the carrier is frequently pulled in can be provided. The synchronization pull-in can be avoided and the time can be further shortened.

  Here, in the above-described demodulator, in each of the first to fourth steps and the sub-steps in the fourth step executed by each component, each execution content is subjected to signal conversion processing. It may be configured to be programmed and executed by a computer as a sub-processing function in the function, the reproduced carrier signal generation function, the signal point position detection processing function, the control signal generation processing function, and the control signal generation processing function.

Even in this case, the processing equivalent to the processing contents in the first to fourth steps and the sub-steps of the fourth step can be executed by the computer. The same object as the detection method can be achieved efficiently.
In the above-described embodiment, only a modulator using QPSK modulation is illustrated. However, the present invention is not limited to QPSK modulation, and is similarly applied to a modulator using PSK or a multilevel QAM modulation method. It can be done.

It is a block diagram which shows the internal structure of the demodulator concerning one Embodiment of this invention. 3 is a flowchart illustrating an operation of the demodulator disclosed in FIG. 1. It is a flowchart which shows the other operation | movement part attached to the flowchart disclosed in FIG. It is explanatory drawing quoted in order to demonstrate operation | movement of the demodulator disclosed in FIG. 7 is a flowchart showing another operation of the demodulator disclosed in FIG. 1. FIG. 2 is an explanatory diagram illustrating operation timing of the demodulator disclosed in FIG. 1. It is a block diagram which shows the demodulator concerning a prior art example. FIG. 8 is an explanatory diagram illustrating operation timing of the demodulator illustrated in FIG. 7. FIG. 8 is an explanatory diagram illustrating other operation timings of the demodulator illustrated in FIG. 7. It is explanatory drawing for demonstrating the state of the pseudo pull-in of the carrier wave in QPSK modulation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Quadrature detector 2 Oscillator 3 A / D converter 4 Carrier recovery apparatus 5 Frame synchronization circuit 40 Carrier recovery part 44 Phase rotator 45 Phase error detector 46 LPF
48 Adder circuit 50 Reproduced carrier signal region determining unit (Reproduced carrier signal region determining circuit)
59 Numerical Control Oscillator 60 Phase Control Signal Area Determination Control Unit 64 APC Signal Area Determination Circuit 67 Sweep Circuit 70 C / N Estimation Circuit 80 Synchronization Detection Circuit 90 Intermittent Reset Signal Generation Circuit

Claims (12)

A carrier wave reproducing unit that detects a phase error between the orthogonally transformed digital signal and the reference signal to generate a phase control signal and generates a reproduced carrier signal based on the phase control signal;
A reproduced carrier signal region determining unit that detects a position of a pseudo pull-in signal point of the reproduced carrier signal based on a signal point position in which the reproduced carrier signal is previously mapped on a phase plane;
A phase control signal region determination control unit that generates a control signal for avoiding synchronous pull-in at the pseudo pull-in signal point position based on a phase control signal at the pseudo pull-in signal point position of the reproduced carrier signal;
A carrier wave reproducing apparatus comprising: In the carrier wave reproducing device according to claim 1,
The carrier recovery unit,
A phase error detector that detects the phase error and generates a phase error signal having a value corresponding to the phase advance and delay of the reproduced carrier signal, and a high-frequency component from the phase error signal output by the phase error detector A low-pass filter that outputs the phase control signal without the output, a numerically controlled oscillator that converts the phase control signal output by the low-pass filter into control angle information corresponding to the angle, and a control angle that is output by the numerically controlled oscillator A phase rotator for performing phase rotation control on the reproduced carrier wave signal based on the information;
A carrier wave reproducing apparatus comprising: In the carrier wave reproducing device according to claim 1,
The reproduced carrier signal region determination unit
A first carrier area centered on the signal point position of the reproduced carrier signal in the normal state and the reproduced carrier signal mapped in the pseudo pull-in are in a region where the reproduced carrier signal is divided and allocated on the phase plane. And a function of generating a pseudo pull-in state detection signal when the ratio belonging to the second area is equal to or greater than a preset value. A carrier wave reproducing device characterized by that. In the carrier wave reproducing device according to claim 1,
In the carrier wave reproduction unit,
A carrier wave / noise ratio estimation circuit that calculates a carrier wave / noise ratio based on the reproduced carrier wave signal and compares the calculated carrier wave / noise ratio with a preset carrier wave / noise ratio, and the carrier wave / noise ratio estimation A carrier recovery apparatus comprising: a synchronization detection circuit that detects synchronization or asynchronousness of the recovered carrier signal based on a comparison calculation result by a circuit and a determination result by the recovered carrier signal region determination unit. In the carrier wave reproducing apparatus according to claim 1 or 4,
The phase control signal region determination control unit
In the pseudo pull-in state, when the synchronization detection unit detects synchronization of the reproduced carrier signal and a frame synchronization detection circuit that detects synchronization / asynchronism in a frame period externally connected in advance detects asynchronous, A phase control signal region determination circuit for determining a control value of a phase control signal as the pseudo pull-in signal point position;
A sweep circuit that generates a control signal that avoids synchronous pull-in at the pseudo pull-in signal point position based on a determination result by the phase signal region determination circuit;
A carrier wave reproducing apparatus comprising: In the carrier wave reproducing device according to claim 5,
The sweep circuit comprises:
When the reproduced carrier signal transitions from an asynchronous state to a synchronous state, the control value immediately before the transition of the control signal is retained, and the control signal is generated based on the retained control value and output to the carrier regeneration unit A carrier recovery device having a function of In the carrier wave reproducing apparatus according to claim 1 or 5,
A carrier recovery apparatus comprising: an intermittent reset signal generation circuit for prohibiting generation of a reproduced carrier signal by the carrier recovery unit when the synchronization detection circuit detects an asynchronous state.   The carrier wave recovery device according to any one of claims 1 to 7 and an incoming reception modulated wave signal provided in an input stage of the carrier wave recovery device are converted into mutually orthogonal baseband signals based on a reference frequency signal. A demodulator comprising: a quadrature detector that converts the baseband signal into a digital signal. A method of detecting a pseudo carrier wave in a demodulator that demodulates an incoming received modulated wave signal,
A first step of converting the received modulated wave signal into baseband signals orthogonal to each other and converting the converted baseband signal into a digital signal;
A second step of generating a phase control signal by detecting a phase error between the orthogonally-transformed digital signal and a preset reference signal and generating a regenerated carrier signal based on the phase control signal;
A third step of detecting a pseudo lead-in signal point position of the reproduced carrier signal based on a signal point position where the generated reproduced carrier signal is mapped on a phase plane;
A fourth step of generating a control signal for avoiding synchronous pull-in at the pseudo pull-in signal point position based on a phase control signal at the pseudo pull-in signal point position of the reproduced carrier signal;
A method for detecting a pull-in of a carrier wave, comprising: In the method of detecting pseudo pull-in of a carrier wave according to claim 9,
In the fourth step, when the recovered carrier signal transitions from an asynchronous state to a synchronous state, the control value immediately before the phase control signal is held and the control signal is generated based on the held control value A method for detecting the pull-in of a carrier wave, comprising substeps. A program for detecting a pseudo pull-in state of a carrier wave in a demodulator that demodulates an incoming received modulated wave signal,
A signal conversion processing function for converting the received modulated wave signal into baseband signals orthogonal to each other and converting the converted baseband signal into a digital signal;
A reproduced carrier signal generation function for generating a phase control signal by detecting a phase error between the orthogonally transformed digital signal and the reference signal, and generating a reproduced carrier signal based on the phase control signal;
A pseudo acquisition signal point position detection processing function for detecting a pseudo acquisition signal point position of the reproduction carrier signal based on a signal point position where the generated reproduction carrier signal is mapped on a phase plane;
A control signal generation processing function for generating a control signal for avoiding synchronous pull-in at the pseudo pull-in signal point position based on a phase control signal at the pseudo pull-in signal point position of the reproduced carrier signal, and outputting the control signal to the carrier regenerator;
A program for detecting the pull-in of a carrier wave, characterized in that the program is executed by a computer. In the carrier pull-in detection program according to claim 11,
The control signal generation processing function holds the control value immediately before the phase control signal and generates the control signal based on the held control value when the reproduced carrier signal transitions from an asynchronous state to a synchronous state. Including sub-processing functions
A program for detecting the pull-in of a carrier wave, characterized by causing a computer to execute this.

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